2016 was a particularly bad year for celebrity deaths, judging by the many mourners on social media platforms like Twitter and Facebook. But verifying that the year was unusually lethal for stars is tricky.

For one thing, celebrity is a subjective quality, and the claim that more celebrities died in any given year is not easily supportable with objective data.

But that has not stopped different media companies, including The New York Times, from trying. The British Broadcasting Corporation and Legacy.com, a company that produces online obituaries with funeral homes and newspapers (among them The Times), began investigating the perceived phenomenon this spring, when they first noticed a spate of sorrowful emails and social media posts about the high number of celebrity deaths. Both concluded that there was an unusual proliferation of them in 2016, though each used a different method to support that claim.

The BBC compared the number of what it called “pre-prepared” obituaries — those written in advance of a person’s death — that ran in 2016 to the number that appeared in previous years, going back to 2012. In December, the BBC published an article saying that it ran 49 such obituaries on radio, television or online in 2016, compared to 32 in 2015.

“Since I’ve been doing this job, for 10 years, we’ve never used this many obituaries,” Nick Serpell, the BBC’s obituary editor, said in a recent telephone interview, referring to obituaries written in advance.

Mr. Serpell acknowledged that using the number of obituaries written in advance as an indicator of major deaths was “flawed,” but said he thought it was “the only way to measure something.”

“Obviously we have people in the U.K. who you’ve never heard of who are famous for us, and you’ve got people that we’ve never heard of, usually linebackers from American football,” he said.

Legacy.com’s study was conducted by Linnea Crowther, a senior writer of obituaries for public figures and other articles. She tried to avoid the problem of subjective judgment by focusing on people she regarded as broadly famous. She compared the number of deaths of famous people that Legacy.com wrote about in 2016 with those going back to 2010, assigning relative levels of fame by starting with her own opinion, monitoring the reaction to the death on social media and consulting her colleagues.

“The lists I compiled were a little subjective, to be sure,” Ms. Crowther wrote about her methodology. “There’s no truly objective way to rank people as really famous or pretty famous versus just a little noteworthy. But what I strove to do was to be as consistent as possible as I looked at the people who have died over the past seven years.”

In a recent telephone interview she acknowledged that the lists were still somewhat subjective.

“It’s kind of a data project, but it’s not quite as objective as a purely data project would be,” Ms. Crowther said.

She maintained that most people would agree that the celebrities she counted merited the designation.

“Everybody has slightly different ideas about what constitutes celebrity,” she said. “If you look at Wikipedia’s list of celebrities, there are more than 6,000, and some of them are horses. Those didn’t make it to my list.”

Ms. Crowther released her results and conclusions in quarterly posts, the last one published during the first week of 2017. Major celebrities she counted in the fourth quarter of 2016 included Carrie Fisher, Janet Reno, Florence Henderson and Fidel Castro. Among the second tier of celebrities she cited the actor Ron Glass, who was familiar to audiences from his work on TV shows like “Firefly” and “Barney Miller.”

Ms. Crowther counted a total of 95 celebrity deaths in 2016, compared with an annual average of 59 for the years 2010 through 2015. She counted 32 major celebrity deaths in 2016 compared with an annual average of 13 for the six previous years.

Ms. Crowther also counted an unusually high number of deaths in the first quarter of 2016. She noted that the average age of people whose deaths she measured in 2016 was 74.2, slightly younger than the 2010-15 average of 76.7, and that an unusually large number of the deceased — like David Bowie, Sharon Jones and George Michael — came from the music world.

The Times, in its own assessment of the incidence of major deaths in 2016, used two different subjective measurements, neither a perfect indicator of celebrity. Most of what was found supported the conclusions of the BBC and Legacy.com, except for one crucial difference.

First we counted the number of people in our Notable Deaths interactive feature, an annual collection of prominent obituaries. In 2016 there were 357 obituaries in Notable Deaths, 56 more than the 301 entries in 2015. In the first four months of 2016, 135 people were added to the feature, substantially more than in most four-month periods. In January alone, 41 were added, the most in any single month since 2012.

Notable Deaths has grown significantly larger every year since it was created in 2010, which seems to support the trend noted by Legacy.com and the BBC.

Next we counted the number of obituaries that appeared on the front page of the newspaper in 2016 and 2015, either as an article, a photograph or an item in the short summaries that appear at the bottom of the page. Most of these obituaries were also promoted on The Times’s home page and in its social media accounts.

In 2015, 31 obituaries ran on the front page compared with 29 in 2016. A total of 147 obituaries were mentioned on the front page in 2015 and just 135 in 2016. In January 2016, 25 obituaries appeared on the front page, the most of any single month.

So 2016 represented either the latest year of increasing celebrity deaths or a small step back from 2015, depending on the metric The Times used.

Of course, there are obvious problems with both of these measurements, as there are with those used in the other studies, because they are based on subjective judgments.

Placement in The Times is a result of editorial decisions; some deaths that might otherwise be reported on the front page, for example, could be displaced by other news — particularly in an election and Olympic year. The opposite could be true for the Notable Deaths feature, which grew in part because of decisions to expand it by recognizing important but lesser-known subjects.

An obituary on the front page of The Times is also not reserved for conventional celebrities. Some are there because the subjects made fascinating contributions to the world but never found wide fame. (Exceptional writing may have also helped push some obituaries onto Page 1.)

One such obituary, for Tyrus Wong, the artist and Disney animator who gave “Bambi” its signature look, became the first front-page obituary of 2017, on Jan. 1.

Even if 2016 was an unusually heavy year for celebrity deaths, the number may seem typical a few years from now. Both Mr. Serpell and Ms. Crowther said that deaths of major figures had been trending upward in the years they examined and that they expected the trend to continue.

They speculated that was a reflection in part of the widespread embrace of television in the 1950s and ’60s; those generations of stars are now passing from the scene.